I had a quick search for this on the forum and couldn't find any information about it, so I thought that I'd post it here to help out anyone who is trying to use RTIViewer on a high DPI display.
On some computers with High DPI displays the RTIViewer program doesn't scale up properly, leaving the buttons too small and the text no longer fits on them, as below:
To fix this we need to tell Windows 10 not to try and scale up the program intelligently, but to run it at its native resolution and magnify the whole thing. This may leave icons and text a little blurry, but it makes the program usable.
To do this we download the manifest file linked at the bottom of the page, then move this manifest file to the same place that you installed RTIViewer; usually C:/Program Files/RTIViewer by default.
Then we need to tell Windows to look for manifest files when opening programs. To do this we open regedit.exe by pressing the windows key, typing run, pressing Enter, typing regedit, and pressing enter. We then use regedit to find the registry subkey HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > SideBySide in the left sidebar, then right-click in the main window and select New > DWORD (32 bit) Value.
Name this PreferExternalManifest then press enter, before right-clicking it and choosing Modify. Give it a decimal value of 1, then press Okay and close regedit.Now when you restart or reopen RTIViewer it should obey system scaling.